Semiconductor and micromechanical chips are typically formed starting with a wafer, typically a silicon wafer. The wafer is typically round and about 300 mm in diameter, however, other wafer shapes are also occasionally used. The chips are formed on the surface of the wafer using a variety of different process chambers that may involve plasma, vapor deposition, photo-lithography and mechanical processes such as grinding, machining, and drilling. The circuits and other components formed on the wafer are normally quite thin and make up only a small part of the thickness of the wafer.
In order to make semiconductor and micromechanical chips smaller, there are efforts to reduce the thickness of the wafer that forms the substrate on which the active circuitry is formed. One way to reduce the thickness of the wafer is to grind the backside of the wafer after the circuits have been formed on the front side. Another way is to use a thinner wafer from the beginning. Unfortunately thin wafers warp and break easily. In order to prevent warpage and breaking, a thick wafer is first bonded to a glass or silicon substrate using an adhesive. After, bonding, the front side of the wafer is thinned, typically by mechanical grinding. The circuits and other components are then formed on the front side of the wafer. The completed thinned wafer is then de-bonded from the substrate.